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The pulse crop lentil (Lens culinaris Medik.) is often grown in crop rotations to provide nitrogen (N) and water benefits for subsequent crops. Lentil yields vary greatly with environmental factors and management. A reliable crop model for lentil could assist efforts to assess the effects of management practices to mitigate environmental stresses and maximize lentil yields. However, few crop models simulate the development and growth of lentil. In this study, we adapted the CSM-CROPGRO model in the Decision Support System for Agrotechnology Transfer to simulate lentil development and growth based on data collected from six experiments conducted from 2001 to 2021 globally. The initial parameter values taken from faba bean (Vicia faba L.) were modified based on reported information and analysis of observed data. Those values were fine-tuned to minimize the gaps between the simulated and observed crop attributes. The model simulated well development stages with root mean square error (RMSE) of 4 days and aboveground biomass with normalized root mean square error (nRMSE ≤ 23%). Seed yields were generally well simulated across experiments in calibration and validation (nRMSE = 19%) datasets, except for overestimation under the humid environment of Quebec in Canada, which may have resulted from excessive vegetative growth. The underlying mechanisms leading to excessive vegetative growth need to be explored further and included in the model for evaluating the adaptability of lentils to specific regions. Overall, the CSM-CROPGRO-Lentil model is ready for simulating lentil production under various scenarios, which may identify ways to improve the productivity and resiliency of cropping systems that include lentil. [ABSTRACT FROM AUTHOR]

Selection during plant domestication and improvement often decreases genetic variation, including variation that confers adaptation to local conditions. We report spatial and temporal variation in fitness (seed yield), local adaptation, and segregating genetic variation within three races of common bean (Phaseolus vulgaris L.) with differing domestication histories and genetic diversities. Three‐hundred and twenty‐seven common bean genotypes had seed yield measured at subsets of 70 sites across North America between 1981 and 2015, as part of the Cooperative Dry Bean Nursery (CDBN). We estimated local adaptation using the metric home field advantage (HFA) and segregating genetic variation using heritability. The Durango and Mesoamerican races (Middle American genepool) had higher‐than‐expected (p =.002) HFA, equal to up to 34 yr of average yield gains. Surprisingly, Nueva Granada (Andean genepool) and Durango yields became more heritable across the study period (p <.001), while Mesoamerican heritability decreased (p <.001). Both metrics detected diversity loss corresponding to the timings of major historical gene introgressions. Local adaptation remains an agronomically important phenomenon within some common bean races. Common bean adaptation to new conditions will be most rapid at locations with large local adaptation benefits and high heritability. Core Ideas: Selection history affects genetic variation, which enables adapting crops to new environments and climates.We report spatiotemporal variation in dry bean yield, local adaptation, and segregating genetics.Yields became more heritable in two of three dry bean races across North America over 35 yr.Local adaptation (home field advantage) was worth up to 34 yr of average breeding gains.Sites with high heritability and home field advantage are best for adapting to new environments. [ABSTRACT FROM AUTHOR]

Ecosystems across the United States are changing in complex and unpredictable ways and analysis of these changes requires coordinated, long‐term research. This paper is a product of a synthesis effort of the U.S. National Science Foundation funded Long‐Term Ecological Research (LTER) network addressing the LTER core research area of "populations and communities." This analysis revealed that each LTER site had at least one compelling "story" about what their site would look like in 50–100 yr. As the stories were prepared, themes emerged, and the stories were group into papers along five themes: state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the cascading effects theme and includes stories from the Bonanza Creek (boreal), Kellogg Biological Station (agricultural and freshwater), Palmer (Antarctica), and Harvard Forest (temperate forest) LTER sites. We define cascading effects very broadly to include a wide array of unforeseen chains of events that result from a variety of actions or changes in a system. While climate change is having important direct effects on boreal forests, indirect effects mediated by fire activity—severity, size, and return interval—have large cascading effects over the long term. In northeastern temperate forests, legacies of human management and disturbance affect the composition of current forests, which creates a cascade of effects that interact with the climate‐facilitated invasion of an exotic pest. In Antarctica, declining sea ice creates a cascade of effects including declines in Adèlie and increases in Gentoo penguins, changes in phytoplankton, and consequent changes in zooplankton populations. An invasion of an exotic species of lady beetle is likely to have important future effects on pest control and conservation of native species in agricultural landscapes. New studies of zebra mussels, a well‐studied invader, have established links between climate, the heat tolerance of the mussels, and harmful algal blooms. Collectively, these stories highlight the need for long‐term studies to sort out the complexities of different types of ecological cascades. The diversity of sites within the LTER network facilitates the emergence of overarching concepts about trophic interactions as an important driver of ecosystem structure, function, services, and futures. [ABSTRACT FROM AUTHOR]

Volatile nitrogen oxides (N2O, NO, NO2, HONO, ...) can negatively impact climate, air quality, and human health. Using soils collected from temperate forests across the eastern United States, we show microbial communities involved in nitrogen (N) cycling are structured, in large part, by the composition of overstory trees, leading to predictable N‐cycling syndromes, with consequences for emissions of volatile nitrogen oxides to air. Trees associating with arbuscular mycorrhizal (AM) fungi promote soil microbial communities with higher N‐cycle potential and activity, relative to microbial communities in soils dominated by trees associating with ectomycorrhizal (ECM) fungi. Metagenomic analysis and gene expression studies reveal a 5 and 3.5 times greater estimated N‐cycle gene and transcript copy numbers, respectively, in AM relative to ECM soil. Furthermore, we observe a 60% linear decrease in volatile reactive nitrogen gas flux (NOy ≡ NO, NO2, HONO) as ECM tree abundance increases. Compared to oxic conditions, gas flux potential of N2O and NO increase significantly under anoxic conditions for AM soil (30‐ and 120‐fold increase), but not ECM soil—likely owing to small concentrations of available substrate (NO3‐) in ECM soil. Linear mixed effects modeling shows that ECM tree abundance, microbial process rates, and geographic location are primarily responsible for variation in peak potential NOy flux. Given that nearly all tree species associate with either AM or ECM fungi, our results indicate that the consequences of tree species shifts associated with global change may have predictable consequences for soil N cycling. [ABSTRACT FROM AUTHOR]

Biosolids land application is governed by N content and estimates of potentially available N (PAN). Amino sugar test N (AST‐N) has been used with varying success to estimate soil responsiveness to N and optimum N rates. We investigated the utility of an amino sugar test (AST) in estimating PAN and hypothesized that this would depend on biosolids type, rate, and receiving soil. In vitro, we applied three dissimilar biosolids at five rates to four representative southeastern US soils, measured AST‐N, and estimated recovery of biosolids AST‐N. Target PAN rates were zero to two times a realistic yield expectation rate (127 kg N ha−1) for a common biosolids‐receiving grass. Rates were based on biosolids type, total N, and book‐value availability coefficients. Biosolids AST‐N varied from 263 to 9790 mg kg−1 (3.8–20.1% of total N). Soil AST‐N was 66–93 mg kg−1 and differed among soils. Treatment interactions indicated that AST‐N of the biosolids–soil mixtures differed from what might be predicted from biosolids and soil AST‐N and rate. Rate response was linear; thus, the AST did not saturate at the rates tested. Biosolids AST‐N recovery ranged from −303 to 152% depending on biosolids, rate, soil, and their interactions. The AST‐N was related linearly to total N from anaerobic incubation (R2 = 0.10–0.67), depending on biosolids. The weakness of these relationships; the biosolids, rate, and soil interactions; and the potential confounding effects of biosolids and soil NH4–N suggest that AST‐N would not be a good estimator of PAN. [ABSTRACT FROM AUTHOR]

Intraspecific niche divergence is an important driver of species range, population abundance and impacts on ecosystem functions. Genetic changes are the primary focus when studying intraspecific divergence; however, the role of ecological interactions, particularly host‐microbiome symbioses, is receiving increased attention. The relative importance of these evolutionary and ecological mechanisms has seen only limited evaluation. To address this question, we used Microcystis aeruginosa, the globally distributed cyanobacterium that dominates freshwater harmful algal blooms. These blooms have been increasing in occurrence and intensity worldwide, causing major economic and ecological damages. We evaluated 46 isolates of M. aeruginosa and their microbiomes, collected from 14 lakes in Michigan, USA, that vary over 20‐fold in phosphorus levels, the primary limiting nutrient in freshwater systems. Genomes of M. aeruginosa diverged along this phosphorus gradient in genomic architecture and protein functions. Fitness in low‐phosphorus lakes corresponded with additional shifts within M. aeruginosa including genome‐wide reductions in nitrogen use, an expansion of phosphorus assimilation genes and an alternative life history strategy of nonclonal colony formation. In addition to host shifts, despite culturing in common‐garden conditions, host‐microbiomes diverged along the gradient in taxonomy, but converged in function with evidence of metabolic interdependence between the host and its microbiome. Divergence corresponded with a physiological trade‐off between fitness in low‐phosphorus environments and growth rate in phosphorus‐rich conditions. Co‐occurrence of genotypes adapted to different nutrient environments in phosphorus‐rich lakes may have critical implications for understanding how M. aeruginosa blooms persist after initial nutrient depletion. Ultimately, we demonstrate that the intertwined effects of genome evolution, host life history strategy and ecological interactions between a host and its microbiome correspond with an intraspecific niche shift with important implications for whole ecosystem function. [ABSTRACT FROM AUTHOR]

Permafrost thaw is leading to rapid shifts in boreal ecosystem function. Permafrost thaw affects soil carbon turnover through changes in soil hydrology; however, the biotic mechanisms regulating plant community response remain elusive.Here, we measured the response of fungal community composition and soil nutrient content in an intact permafrost plateau forest soil and an adjacent thermokarst bog and evaluated their potential to mediate shifts in plant composition.We used barcoded amplicon targeting ITS2 and 28S rRNA genes to determine fungal community composition. Next, we used the soils from the permafrost plateau and the thermokarst bog as soil inoculum in a greenhouse experiment to measure whether shifts in fungal community and soil water level regulate plant productivity and composition.Overall, we found that fungal community composition differed significantly between the thawed and intact permafrost sites, but soil nutrient content did not. Relative abundance of mycorrhizal fungal taxa decreased while relative abundance of putative fungal pathogens increased with permafrost thaw. In the greenhouse, we found that ecto‐ and arbuscular‐associated host plants had higher productivity in permafrost‐intact soils relative to thawed soils. However, productivity of non‐mycorrhizal tussock grass was more affected by soil water levels than soil communities.Synthesis. Our results suggest that fungal communities are crucial in mediating plant community response to permafrost thaws inducing hydrology changes. [ABSTRACT FROM AUTHOR]

Background: With the increasing birth prevalence of hypospadias, there is growing concern for pollutant exposure interfering with normal penile development. We assess the association between hypospadias and hormonally active hazardous air pollutants (HAHAPs) through a nationwide database of hazardous air pollutants and the Texas Birth Defects Registry (TBDR). Methods: Using the TBDR, we identified 8,981 nonsyndromic isolated hypospadias cases from 1999 to 2008. Birth certificate controls were matched for birth year at a 10:1 ratio to cases. Estimated HAHAP concentrations from the 2005 U.S. EPA National‐Scale Air Toxics Assessment were used to assign exposure based on maternal residence at birth. Exposure levels were categorized as quintiles based on the distribution in controls. Logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) for each increasing exposure category of selected HAHAPs. Results: Of the 10 HAHAPs studied, seven were significantly associated with hypospadias risk. The HAHAP that was most strongly associated with hypospadias was phenol, which was associated with risk in all groups except the high exposure group. Cumulative HAHAP exposure demonstrated a modest increase in hypospadias risk (OR 1.15, 95% CI: 1.07–1.24, p < 0.001) in the medium and medium–high quintiles. Conclusions: While maternal exposure to some HAHAPs was significantly associated with the risk of hypospadias in male offspring, the effects were modest, and no dose–response effects were observed. Future work should employ biomarkers of exposure to better delineate the relationship. [ABSTRACT FROM AUTHOR]

Objective: To determine if serum S100B increases similarly as a result of playing American football compared to exercise alone. Methods: Serum S100B was measured in division III collegiate football players before and after every home game during a single football season. Serum S100B was also measured before and after subjects walked on a treadmill for 30 minutes at a leisurely pace, ran on a treadmill while wearing and not wearing a football helmet at 6 mph for 8 minutes, and performed low‐, moderate‐, or high‐intensity resistance exercise. Results: Serum S100B increased significantly (P < 0.05) when subjects played in a football game, ran on a treadmill, or performed moderate‐intensity resistance exercise. Pre‐game serum S100B did not accumulate throughout the football season in any of the players (P > 0.05). The increase in serum S100B during football games was moderately and significantly correlated with both the number of hits (R2 = 0.407) and the number of plays (R2 = 0.484) that each player experienced (P < 0.001). Post‐game serum S100B was greater in football players who played more than 50 plays compared to those players who played <50 plays, subjects who exercised on a treadmill, or subjects performing resistance exercise (P < 0.05). Conclusion: It is unclear if the higher S100B concentration in football players playing at least 50 plays was caused by exercise or hits. Therefore, if serum S100B is to be used as a biomarker of impacts, and possible brain injury in sport, exercise time and intensity should be taken into account as confounding variables. [ABSTRACT FROM AUTHOR]

Seven-day anaerobic incubation can provide relatively quick and easy estimates of potentially available N (PAN), but has been little used to estimate N availability coefficients (NAC) of biosolids destined for land application. We hypothesized that waterlogged-incubation estimates of PAN and NAC depend on biosolids type, application rate, and receiving soil. We applied three dissimilar biosolids at five rates to four representative southeastern US soils and measured NH4-N and NO3-N after a 7-d laboratory waterlogged incubation. Target PAN rates were 0, 0.5, 1, 1.5, and 2' a realistic yield expectation (RYE) rate, 127 kg N ha-1, for tall fescue (Festuca arundinacea), a common biosolids-receiving grass. Biosolids application rates were based on biosolids types, associated book-value NACs, and biosolids total N. Anaerobic incubation of soil plus biosolids yielded predominantly NH4-N. There were three-way biosolids × rate × soil interactions for NH4-N, PAN, and NAC. The PAN differed substantially among biosolids, rates, and receiving soils, ranging from -12.1 to 146 mg kg-1, while NAC ranged from -0.13 to 0.86. Negative values suggested N lost via denitrification or immobilization. The PAN trends reflected biosolids total N. At the highest application rate, soil had no detectable effect on the NAC; otherwise, soil affected NAC by as much as an order of magnitude. Presuming anaerobic incubation provides reasonable estimates of PAN, NAC of any particular biosolids might best be estimated via incubation with the receiving soil across an RYE-based range of N application rates, rather than relying on book value NAC. [ABSTRACT FROM AUTHOR]

Abstract: Hyporheic restoration is of increasing interest given the role of hyporheic zones in supporting ecosystem services and functions. Given the prevalence of sediment pollution to waterways, an emerging restoration technique involves the removal of sediment from the interstices of gravel‐bed streams. Here, we document streambed sediment removal following a large, accidental release of fine sediment into a gravel‐bed river. We use this as a natural experiment to assess the impact of fine sediment removal on reach‐scale measures of transient storage and to document the responses of reaches with contrasting morphology (restored vs. unrestored) to changing discharge one‐field season. We conducted a series of conservative solute tracer experiments in each reach, interpreting both summary statistics for the recovered in‐stream solute tracer time series. Additionally, we applied the transient storage model to interpret the results via model parameters, including a Monte Carlo analysis to measure parameter identifiability and sensitivity in each experiment. Despite the restoration effort resulting in an open matrix gravel bed in the restored reach, we did not find the significant differences in most time series metrics describing reach‐scale transport and transient storage. We hypothesize that this is due to enhanced vertical exchange with the gravel bed in the restored reach replacing lateral exchange with macrophyte beds in the unrestored reach, developing a conceptual model to explain our findings. Consequently, we found that the impact of reach‐scale removal of fine sediment is not measureable using reach‐scale solute tracer studies. We offer recommendations for future studies seeking to measure the impacts of stream restoration at the reach scale. [ABSTRACT FROM AUTHOR]

Climate change is driving large changes in the spatial and temporal distributions of species, with significant consequences for individual populations. Community- and ecosystem-level implications of altered species distributions may be complex and challenging to anticipate due to the cascading effects of disrupted interactions among species, which may exhibit threshold responses to extreme climatic events. Toxic, bloom-forming cyanobacteria like Microcystis are expected to increase worldwide with climate change, due in part to their high temperature optima for growth. In addition, invasive zebra mussels ( Dreissena polymorpha) have caused an increase in Microcystis aeruginosa, a species typically associated with eutrophication, in low-nutrient lakes. We conducted a 13-yr study of a M. aeruginosa population in a low-nutrient lake invaded by zebra mussels. In 10 of the 13 years, there was a significant positive relationship between M. aeruginosa biomass and accumulated degree days, which are projected to increase with climate change. In contrast, Microcystis biomass was up to an order of magnitude lower than predicted by the above relationship during the other three years, including the warmest in the data set, following repeated heat-induced mass mortality of D. polymorpha. Thus, the positive relationship between Microcystis biomass and temperature was negated when its facilitating species was suppressed during a series of exceptionally warm summers. Predicting the net response of a species to climate change may therefore require, at minimum, quantification of responses of both the focal species and species that strongly interact with it over sufficiently long time periods to encompass the full range of climatic variability. Our results could not have been predicted from existing data on the short-term responses of these two interacting species to increased temperature. [ABSTRACT FROM AUTHOR]

Interest in the use of active optical sensors for guiding N fertilizer management of crops like wheat has grown rapidly since the mid-1990s. Recently, active optical sensors have been used to assess water status of crops in addition to plant N status. We conducted a 2-yr study on a Casa Grande sandy loam soil in Maricopa, AZ, with durum wheat under an overhead sprinkler system. Uniquely, this study had 10 unrandomized levels of irrigation and five rates of N fertilizer. The objectives were to compare 12 vegetation indices for their ability to distinguish irrigation and N fertilizer rates and to determine how well the vegetation indices estimated biomass, plant N, grain yield, grain N, and yellow berry. The canopy chlorophyll content index, Datt, and Meris terrestrial chlorophyll index were the most consistent vegetation indices in responding well to N, with minimal water effects. No vegetation indices detected water stress with minimal N effect as well as canopy temperature measured with infrared thermometers. Interest in active optical sensors (AOS) for guiding N fertilizer management of crops like wheat (Triticum aestivum L.) has grown rapidly since their introduction in the mid-1990s. Recently, AOS have been used to assess water status of crops in addition to plant N status. Specific vegetation indices (VIs) might assess N stress while minimizing effects of water stress. A 2-yr study (2013-2014) was conducted on a Casa Grande sandy loam soil in Maricopa, AZ, with durum wheat (T. durum Desf) under an overhead sprinkler system. Uniquely, this study had 10 unrandomized levels of irrigation and five rates of N fertilizer. The objectives were to compare 12 VIs for their ability to distinguish irrigation and N fertilizer effects and to determine how well the VIs estimated biomass, plant N, grain yield, grain N, and yellow berry (opaque starchy grain). Two Crop Circle 470 AOS were passed at a fixed height, 1 m above the tallest plants in the field, every 7 to 10 d during the growing season. The normalize difference vegetation indices (NDVIs) showed highly significant response to N rate in three of four growth-stage-years, but significant water and small N effects at Zadoks 32 (early stem elongation) in 2014. The canopy chlorophyll content index (CCCI), DATT (Datt, 1999), and Meris terrestrial chlorophyll index (MTCI) were the most consistent VIs in distinguishing N rates, with minimal water effects. No VIs detected water stress with minimal N effect as well as the infrared thermometer (IRT) measurements of canopy temperature did. [ABSTRACT FROM AUTHOR]

In North Carolina (NC), biosolids land application rates governed by crop nitrogen (N) requirements typically surpass crop phosphorus (P) needs, increasing surface water pollution potential. The NC Department of Environmental Quality (NCDEQ) is considering P-based biosolids application guidelines for some nutrient-impaired watersheds using the P Loss Assessment Tool (PLAT), but important biosolids information is lacking: total P (TP), water-extractable P (WEP), and percent water-extractable P (PWEP). In each of three seasons, we sampled 28 biosolids from 26 participating water resource recovery facilities (WRRFs) and analyzed for TP, WEP, and percent dry matter (DM), from which PWEP and nonsoluble P were calculated. Based on descriptive statistics and an online survey of treatment processes, biosolids were divided into Class A-alkaline, Class A-heat, Class B-slurry, and Class B-cake. The average TP in Class A alkaline stabilized biosolids was more than five times less than the average of the other biosolids, 5.0 vs. 26.6 g/kg, respectively. Averaged over biosolids, WEP and PWEP were 1.4 g/kg and 5.0%, respectively. Stabilization processes appeared to reduce WEP substantially, so biosolids potential soluble-P loss is low. Our data will allow PLAT to be used for biosolids P-loss risk assessments. [ABSTRACT FROM AUTHOR]

Despite their homogeneous appearance, aquatic systems harbour heterogeneous habitats resulting from nutrient gradients, suspended particulate matter and stratification. Recent reports suggest phylogenetically conserved habitat preferences among bacterioplankton, particularly for particle-associated ( PA) and free-living ( FL) habitats. Here, we show that independent of lake nutrient level and layer, PA and FL abundance-weighted bacterial community composition ( BCC) differed and that inter-lake BCC varied more for PA than for FL fractions. In low-nutrient lakes, BCC differences between PA and FL fractions were larger than those between lake layers. The reverse was true for high-nutrient lakes. Nutrient level affected BCC more in hypolimnia than in epilimnia, likely due to hypolimnetic hypoxia in high-nutrient lakes. In line with previous reports, we observed within-phylum operational taxonomic unit ( OTU) habitat preference conservation, although not for all phyla, including the phylum with the highest average relative abundance across all habitats ( B acteroidetes). Consistent phylum-level habitat preferences may indicate that the functional traits that underpin ecological adaptation of freshwater bacteria to lake habitats can be phylogenetically conserved, although the levels of conservation are phylum dependent. Resolving taxa preferences for freshwater habitats sets the stage for identification of traits that underpin habitat specialization and associated functional traits that influence differences in biogeochemical cycling across freshwater lake habitats. [ABSTRACT FROM AUTHOR]

Lakes are important sources of methane (CH4), accounting for 6-16% of natural global CH4 emissions annually. Vertical spatial resolution of CH4 sampling in the water column of lakes is limited because of physical dimensions of sampling devices and sampling-induced mixing. To improve pool-size estimates of carbon, diffusive flux calculations for CH4, and detailed mechanistic understanding of CH4 dynamics in lakes, more precise vertical profiles of dissolved gases through the water column are vital. We investigate the use of commercially available passive diffusion bags (PDBs) to obtain highly resolved (0.5-m increments) vertical profiles of dissolved CH4 concentrations and isotopic composition ( δ13 ). Laboratory experiments determined PDB equilibration time was between 5 d and 9 d for both CH4 concentration and δ13 . During July 2013, PDBs were deployed at intervals of 0.5-m depth for 5 d in two lakes located < 5 km from the southwestern margin of the Greenland ice cap. Data from PDB samples were compared with samples collected using a submersible, electric pump. In both lakes, PDB and pump samples yielded vertical profiles for CH4 concentration and δ13 that were in close agreement (CH4 concentration R2 = 0.998, p < 0.001; δ13 R2 = 0.970, p < 0.001). Overall agreement between PDB and pump samples verifies the applicability of the PDB approach to dissolved CH4 sampling. High-vertical resolution sampling of dissolved gas concentrations and isotopic composition using PDBs can provide more accurate estimates of pool sizes and diffusive fluxes that advance understanding of production, consumption, and emission processes controlling trace gas dynamics in lacustrine environments under warming climate. [ABSTRACT FROM AUTHOR]

Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consistently below the peat surface in bogs, close to the peat surface in poor fens, and above the peat surface in rich fens. However, the largest flux in bogs occurred when dry 30-day averaged antecedent conditions were followed by wet conditions, while in fens and swamps, the largest flux occurred when both 30-day averaged antecedent and current conditions were wet. Drained wetlands exhibited distinct characteristics, e.g. the absence of large flux following wet and warm conditions, suggesting that the same functional relationships between methane flux and environmental conditions cannot be used across pristine and disturbed wetlands. Together, our results suggest that water table and temperature are dominant controls on methane flux in pristine bogs and swamps, while other processes, such as vascular transport in pristine fens, have the potential to partially override the effect of these controls in other wetland types. Because wetland types vary in methane emissions and have distinct controls, these ecosystems need to be considered separately to yield reliable estimates of global wetland methane release. [ABSTRACT FROM AUTHOR]

We quantified the vulnerability of colonies of the bloom-forming cyanobacterium, Microcystis aeruginosa, to grazing by the invasive filter-feeding zebra mussel ( Dreissena polymorpha) as a function of size in both organisms with laboratory feeding experiments., In one experiment, size-selectivity of 16- to 21-mm mussels was assessed for a single M. aeruginosa clone across a wide size range (~5-88 μm median equivalent diameter, ED). Consumption of colonies ≥80 μm median ED (109 μm median maximum linear dimension) was undetectable, indicating a size threshold of grazing invulnerability. Smaller colonies and single cells were consumed at rates similar to a highly palatable alga ( Ankistrodesmus)., In a second experiment, the size-selectivity of three size classes of mussels (8-11, 17-20 and 25-28 mm shell length) was assessed across three size classes of M. aeruginosa (~32-75 μm median ED). There were no systematic differences in the abilities of the different mussel size classes to consume the largest colonies within this size range., An 8-year field survey of the M. aeruginosa population in Gull Lake, MI (U.S.A.), the source of the experimental organisms, revealed that median colony size consistently decreased during each summer, from above to below the size threshold of effective mussel feeding we identified, which suggests major within-season shifts in the overall vulnerability of the M. aeruginosa population to mussel grazing. Variation in the size structure of M. aeruginosa may help explain highly variable effects of D. polymorpha on the dynamics of this harmful phytoplankter within and across systems. [ABSTRACT FROM AUTHOR]

Crop growth models dynamically simulate processes of C, N and water balance on daily or hourly time-steps to predict crop growth and development and at season-end, final yield. Their ability to integrate effects of genetics, environment and crop management have led to applications ranging from understanding gene function to predicting potential impacts of climate change. The history of crop models is reviewed briefly, and their level of mechanistic detail for assimilation and respiration, ranging from hourly leaf-to-canopy assimilation to daily radiation-use efficiency is discussed. Crop models have improved steadily over the past 30-40 years, but much work remains. Improvements are needed for the prediction of transpiration response to elevated CO2 and high temperature effects on phenology and reproductive fertility, and simulation of root growth and nutrient uptake under stressful edaphic conditions. Mechanistic improvements are needed to better connect crop growth to genetics and to soil fertility, soil waterlogging and pest damage. Because crop models integrate multiple processes and consider impacts of environment and management, they have excellent potential for linking research from genomics and allied disciplines to crop responses at the field scale, thus providing a valuable tool for deciphering genotype by environment by management effects. [ABSTRACT FROM AUTHOR]

Increasing interest in deploying multiple types of sensing instruments for agricultural plotlevel observations has created a need for simple, high-clearance vehicles that can be easily maneuvered through crops while minimizing damage due to wheel traffic. We describe a simple cart built from a 2-m-wide by 1.2-m-long steel frame that was welded onto two bicycle frames at a height providing 1 m of vertical clearance. Instruments such as radiometers and infrared thermometers are attached to the frame via arms that are secured with U-bolts. A large, horizontal surface allows mounting data loggers, batteries, or computers. The cart is easily maneuvered by one person on level ground or by two persons on terrain with furrows, berms, or other obstacles. Design sketches and lists of materials are provided in an electronic supplement. The basic design is readily modifiable for different interrow spacings and sensor positions. [ABSTRACT FROM AUTHOR]

Accurate prediction of phenology is required to guide crop management decisions and to predict crop growth and yield. However, the relative importance of photoperiod and vernalization in predicting anthesis dates for spring bread and durum wheat (Triticum aestivum L. and T. durum Desf.) sown in the winter has not been reported. The purpose of this research is to determine the improvement in predicting anthesis dates of spring wheat sown in the winter when photoperiod and vernalization are considered. Observed dates of anthesis were obtained from University of Arizona wheat variety trials conducted at Maricopa, Wellton, and Yuma, AZ. The Cropping Systems Model CROPSIM-CERES as released in DSSAT 4.5 was used to simulate days to anthesis based on temperature, daylength, and vernalization. For 12 bread and durum wheat cultivars, the model predicted days to anthesis with a root mean square error (RMSE) of 7.6 d if all cultivar differences were ignored, 6.4 d considering only differences in thermal time (TT), 6.1 d with differences in TT and daylength response, 6.4 d with TT and vernalization, and 6.2 d with TT, daylength, and vernalization. Consideration of cultivar differences in TT and photoperiod response improved the prediction of days to anthesis for winter-sown spring wheat, but there was no benefit from considering effects of vernalization in CROPSIM-CERES. [ABSTRACT FROM AUTHOR]

Global warming will likely affect carbon cycles in agricultural soils. Our objective was to deploy infrared (IR) warming to characterize the effect of global warming on soil temperature (Ts), volumetric soil-water content (θs), and intrarow soil CO2 efflux (Φs) of an open-field spring wheat (Triticum aestivum L. cv. Yecora Rojo) crop grown in the semiarid desert Southwest. A temperature free-air controlled enhancement (T-FACE) apparatus using IR heaters maintained canopy air temperature above 3.0-m plots by 1.3 and 2.7°C (0.2 and 0.3°C below the targeted set-points) during the diurnal and nocturnal periods, respectively. A randomized complete block (RCB) design with two IR warming treatments (i.e., Heated; Reference) in three replicates was planted on 10 Mar. and 1 Dec. 2008. Intrarow Ts, θs, and Φs were measured from emergence (bare soil) up until inflorescence emergence (canopy closure). Under ample soil water supply with high θ s, midday Φs was 10% greater in Heated [4.1 μmol (CO2) m-2 s-1] compared with Reference [3.7 μmol (CO2) m-2 s-1]. In contrast, as the soil dried and θ s decreased to a greater degree in Heated compared with Reference, a 10% decrease in Φ s occurred in Heated compared with Reference. Overall, θs had the greatest impact on Φs, whereas it was responsive to Ts only under high θs. Accurate predictions of global climate change effects on Φs in agricultural soils require that interactive effects of Ts and θs be coupled. Infrared warming with T-FACE proved to be an effective experimental methodology to investigate these interactive effects. [ABSTRACT FROM AUTHOR]

Decision support tools for agriculture often require meteorological data as inputs, but data availability and quality are often problematic. Difficulties arise with daily solar radiation (SRAD) because the instruments require electronic integrators, accurate sensors are expensive, and calibration standards are seldom available. NASA's Prediction of Worldwide Energy Resources (NASA/ POWER; power.larc.nasa.gov) project estimates SRAD based on satellite observations and atmospheric parameters obtained from satellite observations and assimilation models. These data are available for a global 10 x 10 coordinate grid. The SRAD can also be generated from atmospheric attenuation of extraterrestrial radiation (Q0). We compared daily solar radiation data from NASA/ POWER (SRADNP) with instrument readings from 295 stations (observed values of daily solar radiation, SRADOB) and values estimated by Weather Generator for Solar Radiation (WGEN R) generator. Two sources ofair temperature and precipitation records provided inputs to WGENR: the stations reporting solar data and the NOAA Cooperative Observer Program (COOP) stations. The resulting data were identified as solar radiation valaues obtained using the Weather Generator for Solar Radiation software in con- junction with daily weather data from the stations providing values of observed values ofdaily solar radiation (SRADWG) and solar radiation values obtained using the Weather Generator for Solar Radiation software in conjunction with daily weather data from NOAA COOP stations (SRADCO), respectively. Values of SRADNP for individual grid cells consistently showed higher correlations (typically 0.85-0.95) with SRADOB than did SRADWG or SRADCO. Mean values of SRADOB, SRADWG, and SRADNP for a grid cell usuallywere within 1 MJ m-2 d-1 ofeach other, but NASA/POWERvalues averaged 1.1 MJ m-2 d-1 lower than SRADOB. This bias increased at lower latitudes and during summer months and is partially explained by assumptions about ambient aerosol properties. The NASA/POWER solar data are a promising resource for studies requiring realistic accounting ofhistoric variation. [ABSTRACT FROM AUTHOR]

Gas exchange and water relations were evaluated under full-season in situ infrared (IR) warming for hard red spring wheat ( Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semiarid desert region of the southwest USA. A temperature free-air controlled enhancement (T-FACE) apparatus utilizing IR heaters maintained canopy air temperature above 3.0 m Heated plots of wheat by 1.3 and 2.7 °C (0.2 and 0.3 °C below the targeted set-points of Reference plots with dummy heaters) during daytime and nighttime, respectively. Control plots had no apparatus. Every 6 weeks during 2007-2009 wheat was sown under the three warming treatments (i.e., Control, Heated, Reference) in three replicates in a 3 × 3 Latin square (LSQ) design on six plantings during 4 months (i.e., January, March, September, December), or in a natural temperature variation treatment (i.e., Control) in three replicates in a randomized complete block (RCB) design on nine plantings during 7 months (i.e., January, February, April, June, July, August, October). Soil temperature ( T) and volumetric soil-water content ( θ) were 1.3 °C warmer and 14% lower in Heated compared with Reference plots, respectively. Other than a 1% shading effect, no artifacts on gas exchange or water relations were associated with the IR warming apparatus. IR warming increased carbon gain characteristic of an increase in metabolic rates to higher temperature that may have been attributed to the well-watered wheat crop and the supplemental irrigation that minimized plant-to-air water vapor pressure differences between IR-warmed and nonwarmed plots. Nevertheless, seasonal oscillations in the IR warming response on carbon gain occurred. IR warming decreased leaf water status and provided thermal protection during freeze events. IR warming is an effective experimental methodology to investigate the impact of global climate change on agronomic cropping and natural ecosystems to a wide range of natural and artificially imposed air temperatures. [ABSTRACT FROM AUTHOR]

The article offers information on an irrigation runoff research conducted on residential lawn in California. It mentions that the research was aimed at evaluating the contribution of turf uses of pyrethroids to residues in urban creek sediments of California. It informs that the research involves liquid and granular applications of bifenthrin methyle and ß-cyfluthrin methyl. It concludes that chemical losses in first runoff was up to 0.58 and 0.08 percent of applied for bifenthrin ß-cyfluthrin. It further reveals that chemical runoff fell significantly during over-irrigation and over irrigation events.

There is potential for using the Illinois soil nitrogen test (ISNT) to improve N fertilizer recommendations for crops in the southeastern United States. The ISNT has been previously calibrated to predict N rates for corn (Zea mays L.) in North Carolina. This study evaluated the effects of sampling time, sampling depth, crop rotation, and fertilizer application on soil ISNT-N during a 2-yr period in the humid Coastal Plain and Piedmont regions of North Carolina. Ten sites were repeatedly sampled at 0-to 10-, 10- to 20-, and 20- to 30-cm depths in fill, mid-winter, and spring between October 2006 and May 2007. Illinois soil nitrogen test N, KCl-extractable soil NO3-N and NH4-N, and soil organic matter (SOM) derived by loss-on-ignition (LOT) were evaluated at each sampling. Temporal changes in these soil parameters were evaluated for various crop rotations and N fertilizer applications. Soil ISNT-N decreased with depth and showed significant variation with time at all three depths at all sites. Soil ISNT-N was influenced by crop rotation and tillage but was not significantly affected by N fertilizer applications. Considering all sites together, ISNT-N was well correlated with LOI; however, ISNT-N was not correlated with LOI across time within sites. This suggests that the ISNT measured a fraction of SOM that behaved somewhat independently with time. [ABSTRACT FROM AUTHOR]

Rising research costs, broadening goals, intellectual property rights, and other concerns increase the need for robust management of crop improvement data. The data model of the International Crop Information System (ICIS) allows breeding processes to be recorded unambiguously in a relational database. This paper describes this model, which underlies the Genealogical Management System (GMS) of ICIS. The model recognizes three classes of methods by which genetic material is advanced. Generative methods such as crossing or mutagenesis increase variation. Derivative methods usually involve selection, and maintenance methods conserve the genetic makeup of germplasm, such as in seed multiplications. Unlike systems that only track pedigrees, the model describes steps of selection. Applications are illustrated for self-pollinating, outcrossing, and clonally propagated crops. The ICIS GMS is in use for species including rice (Oryza sativa L.), wheat (Triticum aestivum L.), maize (Zea mays L.), potato (Solanum tuberosum L.), common bean (Phaseolus vulgaris L.), lesquerella [Lesquerella fend/en (Gray) S. Wats.], and witloof chicory (Cichorium intybus L.). The International Rice Information System, based on ICIS, holds more than 2.6 million unique identifiers for germplasm accessions, crosses, populations, and lines, requiring about 900 megabytes of storage space, which can easily be managed on a personal computer. The GMS model appears suited for widespread use in managing data on crop improvement. [ABSTRACT FROM AUTHOR]

Cereal production is strongly influenced by flowering date. Wheat (Triticum aestivum L.) models simulate days to flower by assuming that development is modified by vernalization and photoperiodism. Cultivar differences are parameterized by vernalization requirement, photoperiod sensitivity, and earliness per se. The parameters are usually estimated by com- paring simulations with field observations but appear estimable from genetic information. For wheat, the Vrn and Ppd loci, which affect vernalization and photoperiodism, were logical candidates for estimating parameters in the model CSM-Cropsim-CERES. Two parameters were estimated conventionally and then re-estimated with linear effects of Vrn and Ppd. Flowering data were obtained for 29 cultivars from international nurseries and divided into calibration (14 locations) and evaluation (34 locations) sets. Simulations with a generic cultivar explained 95% of variation in flowering for calibration data (10 d RMSE) and 89% for evaluation data (10 d RMSE), indicating the large effect of environment. Nonetheless, for the calibration data, the gene-based model explained 29% of remaining variation, and the conventional model, 54%. For the evaluation data, the gene-based model explained 17% of remaining variation, and the conventional model, 27%. Gene-based prediction of wheat phenology appears feasible, but more extensive genetic characterization of cultivars is needed. [ABSTRACT FROM AUTHOR]

An accurate and quick soil N test is needed for N fertilizer recommendations for corn (Zea mays L.) for the humid southeastern USA. The Illinois soil N test (ISNT) has been used to distinguish fertilizer-responsive from unresponsive sites in Illinois. We determined relationships between economic optimum N rates (EONR) and ISNT levels in representative southeastern soils in 35 N-response trials in the Piedmont (n = 4) and Middle (n = 8) and Lower (n = 23) Coastal Plains of North Carolina from 2001 to 2004. The ISNT was strongly correlated with EONR for well or poorly drained sites (r² = 0.87 [n = 20] and 0.78 [n = 10], respectively); data were insufficient for establishing correlations for very poorly drained or severely drought-stressed sites. Expressing ISNT on a mass per unit volume basis vs. EONR improved the correlations slightly (r² = 0.88 and 0.79 for well and poorly drained sites, respectively), but these improvements would not justify the necessary soil bulk density determinations. Regressions of ISNT vs. minimum, average, and maximum EONR based on different N-fertilizer cost /corn price ratios (11.4:1, 7.6:1, and 5:1, respectively) showed strong correlations with EONR for well-drained sites (r² = 0.77, 0.87, and 0.87, respectively) and poorly drained sites (r² = 0.84, 0.78, 0.70, respectively). The ISNT-EONR correlations were different among the cost/price ratios for well-drained sites, but not different for poorly drained sites. Because ISNT predicted EONR robustly to different cost/price ratios, ISNT has the potential to modify or replace current N recommendation methods for corn. [ABSTRACT FROM AUTHOR]

Environmental concerns about increasing NO3 levels in watersheds in North Carolina and elsewhere indicate the need for better N fertilizer management. Nitrate levels might be reduced if N rates could be adjusted based on field- or site-specific knowledge of corn (Zea mays L.) response to N fertilization. Currently, there is no effective soil N test for the humid southeastern USA. This study was conducted to compare three soil N tests for practicality, precision, and ability to correlate with economic optimum N rate (EONR) and fertilizer response on southeastern U.S. soils. The soil N tests were the Illinois soil N test (ISNT), the gas pressure test (GPT), and the incubation and residual N test (IRNT). Soil samples were collected from the sites of 16 N-response trials from 2001 to 2003 where different mineralizable and residual N levels were expected. The ISNT was determined to be the most practical test because it was the easiest to perform and could be completed in 1 d. The ISNT and GPT had better precision (lower CV) than the IRNT (9 and 13 vs. 61%, respectively). All three tests were related to EONR; ISNT had the strongest linear relationship (r² = 0.90) when consideration was restricted to sites on mineral soils. The ISNT and GPT were related to delta yield (maximum yield minus check yield; r² = 0.49 and 0.60, respectively) and fertilizer response (r² = 0.31 and 0.51, respectively). These results indicate the potential of the ISNT and GPT to account for mineralizable and residual soil N levels and thus improve current corn N recommendations in the humid southeastern USA. [ABSTRACT FROM AUTHOR]

A person-centered approach to teaching multicultural counseling resulted in a broad array of significant learning experiences. This article describes the instructor's nondirective attitudes, the class-chosen content and process topics, and outcome data. This article also compares and contrasts this approach with conventional and other humanistic multicultural teaching methods. [ABSTRACT FROM AUTHOR]

Presents an edited transcript of the 40th in a series of conferences convened by the U.S. Middle East Policy Council held in Washington, D.C. on June 17, 2005. Effect of the U.S. strategy of insurgency in Iraq; Order of the Kurdish militias' loyalty; Policy issues faced by the U.S. government.

Climate change will directly affect carbon and nitrogen mineralization through changes in temperature and soil moisture, but it may also indirectly affect mineralization rates through changes in soil quality. We used an experimental mesocosm system to examine the effects of 6-year manipulations of infrared loading (warming) and water-table level on the potential anaerobic nitrogen and carbon (as carbon dioxide (CO2) and methane (CH4) production) mineralization potentials of bog and fen peat over 11 weeks under uniform anaerobic conditions. To investigate the response of the dominant methanogenic pathways, we also analyzed the stable isotope composition of CH4 produced in the samples. Bog peat from the highest water-table treatment produced more CO2 than bog peat from drier mesocosms. Fen peat from the highest water-table treatment produced the most CH4. Cumulative nitrogen mineralization was lowest in bog peat from the warmest treatment and lowest in the fen peat from the highest water-table treatment. As all samples were incubated under constant conditions, observed differences in mineralization patterns reflect changes in soil quality in response to climate treatments. The largest treatment effects on carbon mineralization as CO2 occurred early in the incubations and were ameliorated over time, suggesting that the climate treatments changed the size and/or quality of a small labile carbon pool. CH4 from the fen peat appeared to be predominately from the acetoclastic pathway, while in the bog peat a strong CH4 oxidation signal was present despite the anaerobic conditions of our incubations. There was no evidence that changes in soil quality have lead to differences in the dominant methanogenic pathways in these systems. Overall, our results suggest that even relatively short-term changes in climate can alter the quality of peat in bogs and fens, which could alter the response of peatland carbon and nitrogen mineralization to future climate change. [ABSTRACT FROM AUTHOR]

Focuses on the complementary and alternative medicine (CAM) and cancer research in the United States. Prevalence in the usage of CAM; Importance of CAM in oncologic treatment; Improvement of CAM to complement mainstream medicine.

Looks at a study which examines the amount of methane emissions from recognized plants in peatlands. Information on the methane emissions from `Scheuchzeria palustris'; Discussion on the methods used in examining the methane emissions; Determination of methane passing through `Scheuchzeria palustris'; Indebt look at plants that were capable of distributing methane and how they regulated the methane pool.

Presents a study to characterize dissolved organic carbon contribution to acid-based chemistry in acidic peatland soils, while evaluating several analog organic acid models in these soil systems. Methodology used in analysis of field sampling; Estimation of charge deficit in porewaters; Results of the study.

We asked if intraspecific variation within a population of the toxic, bloom-forming phytoplankter, Microcystis aeruginosa, leads to differential vulnerability to grazing by the invasive, filter-feeding zebra mussel (Dreissena polymorpha). We performed two series of laboratory feeding experiments in which D. polymorpha were presented with several different sympatric M. aeruginosa clones in a two-species mixture with the high-quality, nutritious alga, Ankistrodesmus falcatus. Mean selectivity across M. aeruginosa clones ranged from near zero (i.e., no feeding on M. aeruginosa) to near one (equal feeding on the two algal species), evidence of maximal variation in grazing vulnerability across twenty clones of M. aeruginosa--a species assumed to be largely 'inedible' to grazers--from the same population. This range of vulnerability is essentially equal to that typically measured across all phytoplankton species. Large intraspecific variation in grazing vulnerability, and its ecological consequences, could influence the promotion or control of noxious blooms of toxigenic cyanobacteria. [ABSTRACT FROM AUTHOR]

To use shallow groundwater NO3-N concentration as an indicator of groundwater quality requires understanding its patterns, correlations, and controls across space and time. Within a study comparing variable-rate and uniform N management, our objectives were to determine groundwater NO3-N patterns and correlations at various spatial and temporal scales and their association with natural controls and N management. Experiments in a random, complete block design were conducted in a 2-yr crop rotation in North Carolina that included one variable-rate and two uniform N management treatments to wheat (Triticum aestivum L.) and corn (Zea mays L.). We measured groundwater NO3-N and depth every 2 wk at 60 well nests, sampling the 0.9- to 3.7-m depth. Field-mean NO3-N varied with time from 5.5 to 15.3 mg NO3-N L-1. These variations were correlated primarily with concurrent changes in water table elevation and depth. Mean NO3-N exhibited two preferred states: high when the water table was shallow and low when the water table was deep. Temporal NO3-N fluctuations greatly exceeded treatment effects. Treatments appeared to affect NO3-N temporal covariance structure. Groundwater NO3-N spatial patterns and correlations were associated mostly with saturated hydraulic conductivity and water table fluctuations and appeared influenced by subsurface lateral flow. When treatment effects became consistently significant later in the study, they overrode natural controls, and NO3-N was spatially uncorrelated or exhibited shorter spatial correlation ranges and patterns associated predominantly with treatments. [ABSTRACT FROM AUTHOR]